In linguistics, a hyponym (from Greek hupó, "under" and ónoma, "name") is a word or phrase whose semantic field is included within that of another word, its hyperonym or hypernym (from Greek hupér, "over" and ónoma, "name"). In simpler terms, a hyponym is in a type-of relationship with its hypernym. For example, pigeon, crow, eagle and seagull are all hyponyms of bird (their hypernym); which, in turn, is a hyponym of animal.
Hyponymy shows the relationship between a generic term (hypernym) and a specific instance of it (hyponym). A hyponym is a word or phrase whose semantic field is more specific than its hypernym. The semantic field of a hypernym, also known as a superordinate, is broader than that of a hyponym. An approach to the relationship between hyponyms and hypernyms is to view a hypernym as consisting of hyponyms. This, however, becomes more difficult with abstract words such as imagine, understand and knowledge. While hyponyms are typically used to refer to nouns, it can also be used on other parts of speech. Like nouns, hypernyms in verbs are words that refer to a broad category of actions. For example, verbs such as stare, gaze, view and peer can also be considered hyponyms of the verb look, which is their hypernym.
Hypernyms and hyponyms are asymmetric. Hyponymy can be tested by substituting X and Y in the sentence 'X is a kind of Y' and determining if it makes sense. For example, 'A screwdriver is a kind of tool' makes sense but not 'A tool is a kind of screwdriver'.
Strictly speaking, the meaning relation between hyponyms and hypernyms applies to lexical items of the same word class (or parts of speech), and holds between senses rather than words. For instance, the word screwdriver used in the previous example refers to the tool for turning a screw, and not to the drink made with vodka and orange juice.
Hyponymy is a transitive relation, if X is a hyponym of Y, and Y is a hyponym of Z, then X is a hyponym of Z. For example, violet is a hyponym of purple and purple is a hyponym of color; therefore violet is a hyponym of color. A word can be both a hypernym and a hyponym: for example purple is a hyponym of colour but itself is a hypernym of the broad spectrum of shades of purple between the range of crimson and violet.
The hierarchical structure of semantic fields can be mostly seen in hyponymy. They could be observed from top to bottom, where the higher level is more general and the lower level is more specific. For example, living things will be the highest level followed by plants and animals, and the lowest level may comprise dog, cat and wolf.
Under the relations of hyponymy and incompatibility, taxonomic hierarchical structures too can be formed. It consists of two relations; the first one being exemplified in 'An X is a Y' (simple hyponymy) while the second relation is 'An X is a kind/type of Y'. The second relation is said to be more discriminating and can be classified more specifically under the concept of taxonomy.
If the hypernym Z consists of hyponyms X and Y, X and Y are identified as co-hyponyms. Co-hyponyms are labelled as such when separate hyponyms share the same hypernym but are not hyponyms of one another, unless they happen to be synonymous. For example, screwdriver, scissors, knife, and hammer are all co-hyponyms of one another and hyponyms of tool, but not hyponyms of one another: *'A hammer is a type of knife' is false.
Co-hyponyms are often but not always related to one another by the relation of incompatibility. For example, apple, peach and plum are co-hyponyms of fruit. However, an apple is not a peach, which is also not a plum. Thus, they are incompatible. Nevertheless, co-hyponyms are not necessarily incompatible in all senses. A queen and mother are both hyponyms of woman but there is nothing preventing the queen from being a mother. This shows that compatibility may be relevant.
A word is an autohyponym if it is used for both a hypernym and its hyponym. For example, the word dog describes both Canis familiaris and male Canis familaris, so it is possible to say "That dog isn't a dog, it's a bitch" ("That hypernym Z isn't a hyponym Z, it's a hyponym Y"). Similarly, the verb to drink (a beverage) is a hypernym for to drink (an alcoholic beverage). Autohyponymy is also called "vertical polysemy".[a]
The term "autohyponym" was coined by linguist Laurence R. Horn in a 1984 paper, Ambiguity, negation, and the London School of Parsimony. Linguist Ruth Kempson had already observed that if there are hyponyms for one part of a set but not another, the hypernym can complement the existing hyponym by being used for the remaining part. For example, fingers describe all digits on a hand, but the existence of the word thumb for the first finger means that fingers can also be used for "non-thumb digits on a hand".
Horn called this "licensed polysemy", but found that autohyponyms also formed even when there is no other hyponym. Yankee is autohyponymous because it is a hyponym (native of New England) and its hypernym (native of the United States), even though there is no other hyponym of Yankee (as native of the United States) that means "not a native of New England".[b]
In some cases, autohyponyms duplicate existing, distinct hyponyms. The hypernym "smell" (to emit any smell) has a hyponym "stink" (to emit a bad smell), but is autohyponymous because "smell" can also mean "to emit a bad smell", even though there is no "to emit a smell that isn't bad" hyponym.
Hyponymy is the most frequently encoded relation among synsets used in lexical databases such as WordNet. These semantic relations can also be used to compare semantic similarity by judging the distance between two synsets and to analyse Anaphora.
The notion of hyponymy is particularly relevant to language translation, as hyponyms are very common across languages. For example, in Japanese the word for older brother is ani (?), and the word for younger brother is ot?to (?). An English-to-Japanese translator presented with a phrase containing the English word brother would have to choose which Japanese word equivalent to use. This would be difficult, because abstract information (such as the speakers' relative ages) is often not available during machine translation.
Umbrella term is also called a hypernym
Hypernym can also be called an 'Umbrella term'
umbrealla term, or hypernym
Synaptic plasticity is a hypernym (umbrella term)